docs: def view_component_planes(self, dimensions=None, figsize=None,
                                colormap=cm.Spectral_r, colorbar=False,
                                bestmatches=False, bestmatchcolors=None,
                                labels=None, zoom=None, filename=None):
          """Observe the component planes in the codebook of the SOM.
  
          :param dimensions: Optional parameter to specify along which dimension
                             or dimensions should the plotting happen. By
                             default, each dimension is plotted in a sequence of
                             plots.
          :type dimension: int or list of int.
          :param figsize: Optional parameter to specify the size of the figure.
          :type figsize: (int, int)
          :param colormap: Optional parameter to specify the color map to be
                           used.
          :type colormap: matplotlib.colors.Colormap
          :param colorbar: Optional parameter to include a colormap as legend.
          :type colorbar: bool.
          :param bestmatches: Optional parameter to plot best matching units.
          :type bestmatches: bool.
          :param bestmatchcolors: Optional parameter to specify the color of each
                                  best matching unit.
          :type bestmatchcolors: list of int.
          :param labels: Optional parameter to specify the label of each point.
          :type labels: list of str.
          :param zoom: Optional parameter to zoom into a region on the map. The
                       first two coordinates of the tuple are the row limits, the
                       second tuple contains the column limits.
          :type zoom: ((int, int), (int, int))
          :param filename: If specified, the plot will not be shown but saved to
                           this file.
          :type filename: str.
          """
          if self.codebook is None:
              raise Exception("The codebook is not available. Either train a map"
                              " or load a codebook from a file")
          if dimensions is None:
              dimensions = range(self.n_dim)
          for i in dimensions:
              plt = self._view_matrix(self.codebook[:, :, i], figsize, colormap,
                                      colorbar, bestmatches, bestmatchcolors,
                                      labels, zoom, filename)
          return plt